This invention relates generally to gimbal systems and more particularly to gimbal systems adapted for use in guided missile seekers.
As is known in the art, gimbal system are used in a wide range of applications. One such application is in guided missile seekers. More particularly, guided missiles typically include in the frontal portion thereof a seeker, such as a radar, infrared, or electro-optical seeker, disposed within the missile""s body behind a dome (i.e., a radome or IR dome, for example). The seeker is mounted to the interior body of the missile, by a gimbal system, such as a three-degree of freedom pitch-yaw gimbal system or a six-degree of freedom pitch-yaw-roll gimbal system.
The seeker includes a sensor, such as a radar antenna, on IR detector, or a laser energy detector, and associated electronics, such as hybrids, A/D converters. amplifiers, etc, and additional support devices, such as body rate sensors (i.e, gyros), torque motors, and resolvers, etc. Further, the gimbals are driven by motors in response to signals supplied by the missile""s guidance system and fed to the sensors, associated electronics, additional support devices, and motors through cables. In some applications, as many as 70 cables are required for the seeker/gimbal system.
Typically, these cables, or electrical wires, are harnessed and such harness wraps around a gimbal axis to provide a xe2x80x9cservice loopxe2x80x9d configuration to accommodate large gimbal angles. A harness of this size is relatively inflexible; a condition which worsens at cold temperature. Further, there is relatively little space for the harnessed cables.
In accordance with the invention, a system is provided including a slip ring plate and a brush assembly. The disk-shaped slip ring plate is mounted to a first gimbal member and has a plurality of concentric, truncated circular shaped electrical conductive segments disposed on one surface thereof, the electrical conductive segments being electrically insulated from each other. The brush assembly has a like plurality of brushes, each of the brushes being positioned in electrical contact with a corresponding one of the plurality of conductive segments while the brush assembly and disk-shaped ring platter rotate with respect to each other about an axis common to the concentric, truncated circular shaped conductive segments.
In accordance with another embodiment of the invention, a gimbal system is provided including a slip ring plate and a brush assembly. The disk-shaped slip ring plate is mounted to a first gimbal member and has a plurality of truncated circular shaped electrical conductive segments disposed on one surface of thereof, such circular shaped conductors having a common central axis, a plurality of the electrical conductive segments being disposed along a common radius from the central axis, the conductive segments being electrically insulated from each other. The brush assembly has a like plurality of brushes, each of the brushes being positioned in electrical contact with a corresponding one of the plurality of conductive segments while the brush assembly and disk-shaped ring platter rotate with respect to each other about an axis common to the concentric, truncated circular shaped conductive segments.
In accordance with another embodiment of the invention, a gimbal system is provided. A disk-shaped slip ring plate is mounted to a first gimbal member having a plurality of electrically isolated sectors, each one of the sectors having truncated circular shaped electrically insulated conductive segments disposed on the surface, the circular shaped conductors having a common central axis. The system also includes a like plurality of brush assemblies, each one of the assemblies being positioned to electrically contact the segments in a corresponding one of the sectors while the brush assembly and disk-shaped ring platter rotate with respect to each other about an axis common to the concentric, truncated circular shaped conductive segments. Each one of the assemblies includes a plurality of brushes, each of the brushes being positioned in electrical contact with a corresponding one of the conductive segments in the sector associated with such brush assembly.
In accordance with another embodiment of the invention, a system is provided including a housing, a motor, a bearing, a slip ring, a gimbal, an elongate member, a plurality of conductive wires, and a brush assembly. The motor is mounted to the housing, the motor for providing torque to a rotatable portion thereof that is rotatable relative to the housing along an axis. The bearing is mounted to the housing and includes a rotatable portion that is rotatable relative to the housing about the axis. The disk-shaped slip ring includes a surface on which a plurality of arcuate conductors are disposed, the plurality of arcuate conductors being concentric about the axis and separated by at least one electrically insulative discontinuity extending radially from the axis, the slip ring defining an arcuate opening that is concentric about the axis and that is partially defined by endwalls. The gimbal is nonrotatably coupled to the rotatable portion of the motor and to the rotatable portion of the bearing. The elongated member is attached to the gimbal and extends through the arcuate opening. The plurality of conductive wires are each electrically connected to one of the plurality of arcuate conductors. The brush assembly is fixedly attached to the housing and includes a plurality of conductive brushes each electrically contacting one of the plurality of arcuate conductors. When the motor rotates the gimbal, the slip ring is substantially stationary while the elongated member is displaced from the endwalls of the arcuate opening and is urged to rotate about the axis when the elongated member is forced against an endwall of the arcuate opening.
In accordance with another embodiment of the invention, an assembly is provided. The assembly includes a gimbal and a slip ring defining an axis and including a plurality of arcuate conductors that are concentric about the axis, the slip ring further defining an arcuate opening that is concentric about the axis and that is partially defined by endwalls. A elongated member extends from the gimbal through the arcuate opening, the elongated member being configured to move angularly within the arcuate opening when the gimbal and slip ring are rotated with respect to each other about the axis, and to engage the endwalls of the arcuate opening.
In accordance with another embodiment of the invention, an assembly is provided. A gimbal includes a first gimbal engaging surface and a second gimbal engaging surface. An electrically insulative disk is coupled to the gimbal and defines an axis, the disk being rotatable relative to the gimbal about the axis. The disk includes a plurality of arcuate conductors that are concentric about the axis and are disposed on a surface of the disk, a first disk engaging surface, and a second disk engaging surface angularly displaced about the axis from the first disk engaging surface. The first disk engaging surface is disposed to interfere with the first gimbal engaging surface to induce rotation of the gimbal relative to the disk in a first angular direction, and the second disk engaging surface is disposed to interfere with the second gimbal engaging surface to induce rotation of the gimbal relative to the disk in a second angular direction.
Various aspects of the invention may include one or more of the following advantages. Large amounts of conductor runs can pass from one axis to another without typical wire bundling, service loop coiling, or along-axis feed through. Wide angle field of view (FOV) capabilities are provided while also providing low friction to inertia, and accommodating for environmental requirements such as acceleration and vibration, and accommodating look angle and packaging constraints. Large wire counts are provided in highly flexible, non-binding flex prints that can accommodate large rotation angles without requiring a large volume. Conductor runs can be shielded to reduce electromagnetic interference in easily-producible flex print cabling that provides reliable, high-quality performance. Small angle (e.g., 5-10xc2x0) rotation is provided for without significant, if any, slip ring rotation. Slip ring wear is reduced and lifetime lengthened compared to traditional slip rings. Noise between brush contacts and slip ring conductors is reduced, if not eliminated, compared to traditional slip rings. Larger arcuate slip ring travel is provided than the arcuate length of a sector of conductors on a slip ring. Brush contacts slide very little, if at all, on corresponding slip ring conductors during small-angle rotation stabilization of a gimbal. Freely flexible, shielded wiring for a yaw axis is provided. Mechanical flexibility and rotation of the yaw axis of approximately xc2x125xc2x0 using a freely flexing, shield cable are provided. Freely flexing, shielded cabling is provided for the pitch axis. Gimbal system cabling is electromagnetically shielded. A slip ring arrangement can be used with less than a four-inch circumferential conductor length of unshielded conductor. A slip ring is provided that has a more modular, conformed packaging with improved ease of installation and repair, producibility and reliability than traditional slip ring gimbal systems. Electrical contact with conductors of the slip ring can be maintained even if a contact to a conductor breaks or otherwise fails. Wide angle FOV is attainable for the pitch axis with little, if any, wiring restriction or induced cabling torque. An increased number of connector runs can be provided compared to traditional slip ring designs. Yaw cables provide a more flexible, less motion restricted, lower torque, and improved ease of assembly, compared to traditional slip ring gimbal systems. Friction to inertia of the slip ring and brush contacts is reduced compared to traditional slip ring designs, improving performance.